The bore of the trumpet is said to be mostly cylindrical before the flare for the bell begins. It is made of brass bent into a rough spiral, with valves to assist in changing the pitch, or frequency. Sound is produced by vibrating the lips, which vibrates the column of air in the trumpet. The mouthpiece provides a comfortable receiver to allow the lips to play without touching the sharp and restricting edge of the trumpet's tube itself. The sound is projected outward by the bell.

The trumpet is closely related to the cornet and flugelhorn, both of which are more conical in the shape of the bore rather than cylindrical, and have more mellow tones, but are in the same pitch range. The piccolo trumpets play about one octave higher than the regular trumpets. There are also rotary-valve, or German, trumpets, as well as bass, alto and Baroque trumpets. The modern trumpet evolved from earlier non-valved instruments, such as the Baroque trumpet now used by original instruments[?] ensembles, the didjeridu, and the Scandinavianlur.

The trumpet is (usually) a transposing instrument, and comes in many keys. The most common is the B-Flat trumpet, followed by the C, E-Flat, D, and A trumpets. In many countries, including the United States and much of Europe, the (non-transposing) C trumpet is nowadays the standard orchestral instrument.

Piccolo trumpet in Bb - note the swappable leadpipes for Bb and (longer) ALarger version

The piccolo trumpet is built usually in either B-Flat or A, with G, F and even high C piccolos possible but much less common: its tone is metallic and clean. Many piccolos have four valves instead of the usual three: the fourth valve takes the instrument down in pitch, usually but not always by a fourth, to allow the playing of lower notes which are otherwise unobtainable on a three-valve instrument. The bass trumpet is usually played by a trombone player, being at that pitch.

The first trumpets reputedly came from Egypt, and were primarily used for military purposes, like the bugle as we still know it, with different tunes corresponding to different instructions. In medieval times, trumpet playing was a guarded craft, its instruction occurring only within highly selective guilds. The trumpet players were often among the most heavily guarded members of a troop, as they were relied upon to relay instructions to other sections of the army. Eventually the trumpet's value for musical production was seen, particularly after the addition of valves, and its use and instruction became much more widespread.

Trumpets in the Bible
According to Easton's Bible Dictionary, trumpets in the Bible were of a great variety of forms, and were made of various materials. Some were made of silver (Num. 10:2), and were used only by the priests in announcing the approach of festivals and in giving signals of war. Some were also made of rams' horns (Josh. 6:8). They were blown at special festivals, and to herald the arrival of special seasons (Lev. 23:24; 25:9; 1 Chr. 15:24; 2 Chr. 29:27; Ps. 81:3; 98:6). This type of trumpet, the shofar is still blown today in Jewish services on Rosh Hashanah (the Jewish New Year).